Xiong Yi, Xiong Yanli, Shu Xin, Yu Qingqing, Lei Xiong, Li Daxu, Yan Jiajun, Bai Shiqie, Ma Xiao
College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, China.
Sichuan Academy of Grassland Science, Chengdu, China.
Front Plant Sci. 2022 May 19;13:862759. doi: 10.3389/fpls.2022.862759. eCollection 2022.
A detailed understanding of the distribution and degree of genetic variation within a species is important for determining their evolutionary potential, which in return facilitates the development of efficient conservation strategies aimed at preserving adaptive genetic variation. As an important perennial, cool-season grass in temperate Eurasia, increasing attention has been paid to Siberian wildrye () due to its excellent ecological utilization value and forage production potential in China, particularly in the Qinghai-Tibet Plateau (QTP) regions. In this study, we applied two chloroplast (cp) genes ( and ), three cp spacer regions (-∼-, ∼, and ∼-), and six cpSSR markers to the genetic and phylogenetic analysis of 137 wild accessions from 23 natural populations that represent the main distribution regions in China. The results show the highest genetic diversity ( = 0.913) and haplotype richness (10 haplotypes) for the QTP population, which indicates QTP as the probable diversity center and geographic origin of in China. Population divergence was high, indicating a significant phylogeographic structure together with a significantly higher N value (N > G, < 0.05) at the species level, QTP+XJ (combined populations from QTP and Xinjiang), QTP+NC (combined populations from QTP and North China), and XJ+NC (combined populations from Xinjiang and North China) group levels, respectively. An expansion was revealed in the distributional range of in China from paleo times up to the recent past, while a dramatic range of contraction was predicted for the near future. The predicted main limiting factor for the further spread of is an increasing global mean temperature. We recommend that the combination of Es-cpDNA1 and Es-cpDNA3+4+5 can be used as effective markers for phylogenetic analysis and phylogeographical history analysis of . These findings shed new light on the historical population dynamics of cold-season herbs in the QTP region and the north of China and are of great significance for the future establishment of protection and collection strategies for wild germplasm.
详细了解一个物种内遗传变异的分布和程度对于确定其进化潜力很重要，而这反过来又有助于制定旨在保护适应性遗传变异的有效保护策略。作为温带欧亚大陆一种重要的多年生冷季草，由于其在中国，特别是青藏高原地区具有优异的生态利用价值和牧草生产潜力，西伯利亚披碱草受到了越来越多的关注。在本研究中，我们应用两个叶绿体（cp）基因（和）、三个cp间隔区（-∼-、∼和∼-）以及六个cpSSR标记对来自中国主要分布区域的23个自然种群的137份野生披碱草材料进行了遗传和系统发育分析。结果表明，青藏高原种群具有最高的遗传多样性（= 0.913）和单倍型丰富度（10个单倍型），这表明青藏高原可能是中国披碱草的多样性中心和地理起源地。种群分化程度较高，表明在物种水平、青藏高原+新疆（来自青藏高原和新疆的合并种群）、青藏高原+华北（来自青藏高原和华北的合并种群）以及新疆+华北（来自新疆和华北的合并种群）组水平上存在显著的系统地理结构，且N值显著更高（N > G，< 0.05）。研究揭示了中国披碱草从古至今分布范围的扩张，而预测其在不久的将来分布范围将急剧收缩。预测限制披碱草进一步扩散的主要因素是全球平均气温的升高。我们建议，Es-cpDNA1和Es-cpDNA3+4+5的组合可作为披碱草系统发育分析和系统地理历史分析的有效标记。这些发现为青藏高原地区和中国北方冷季草本植物的历史种群动态提供了新的见解，对未来野生披碱草种质资源保护和收集策略的制定具有重要意义。
